docs: add skill install hints

skills/blucli/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: blucli
 description: BluOS CLI (blu) for discovery, playback, grouping, and volume.
-metadata: {"clawdis":{"requires":{"bins":["blu"]}}}
+metadata: {"clawdis":{"requires":{"bins":["blu"]},"install":[{"id":"go","kind":"go","module":"github.com/steipete/blucli/cmd/blu@latest","bins":["blu"],"label":"Install blucli (go)"}]}}
 ---
 
 # blucli (blu)